Study suggests hygiene may lead to more severe allergies

Allergies pose issues that affect, according to the Asthma and Allergy Foundation of America, an upward of one in five Americans every day. These issues can range from mild sensitivities as a result of household dust to life threatening reactions to prescribed drugs.

An allergy is a condition in which the immune system reacts in an unusual way to a foreign substance. It is similar to the way that our bodies would react to a viral or bacterial infection, but more sudden and typically more severe.

Symptoms include rashes, runny noses and swelling, as well as trouble with breathing in some cases.

During the 10-year period from 1997 to 2007, the occurrence of reported food-related allergies in children under the age of 18 increased by 18 percent, according to a report by Amy Branum and Susan Lukacs of the National Center for Health Statistics.

This has led many to speculate about the causes of the surprising rise in incidence. A common theory that has been proposed is the “hygiene hypothesis.”

This theory states that a lack of early exposure to microorganisms, such as bacteria, parasites and other stimuli prevents the immune system from developing properly.

A new study published by Du Toit and his research team in The New England Journal of Medicine in late February of this year lends some support to this hypothesis.

The study researched the development and progression of peanut-based allergies in children and the ways in which early exposure to peanuts may alleviate or even circumvent the condition.

In the study, researchers selected 640 infants, ages four to 11 months, who were determined to be at risk of developing peanut allergies. A skin-prick test was used to determine the level of sensitivity that the infants had prior to the study.

Once sensitivity levels were determined, the children deemed safe for the study were separated into two groups.

One group was composed of children who had no initial sensitivity to peanuts. The other group contained children who already had or were currently developing peanut allergies based on the skin prick results.

Within each of these two groups, the children were randomly assigned to either completely avoid peanuts or to consume at least six grams of peanut protein per week. Final results were determined once the participants reached 60 months (five years) of age.

The results of this study seem to refute the common perception that avoidance of an allergen is the best way to prevent allergy development. In the first group (composed of children without initial sensitivity to peanuts) 13.7 percent of those who avoided peanuts developed an allergic intolerance by the age of five.

In contrast, of the children who regularly ate peanut products, only 1.9 percent developed an allergic intolerance by the age of five. This worked out to an 86 percent reduction in the development of peanut based allergies by the group exposed to peanuts.

Results from the second group of children (those who showed initial sensitivity to peanuts early on) were equally remarkable. Of the children who were already developing peanut allergies and subsequently avoided peanuts, the allergy development rate was 35.3 percent.

On the other hand, those who were regularly consuming peanut products despite early signs of sensitivity only developed allergies 10.6 percent of the time. In this instance, the overall reduction of peanut based allergies in the group exposed to peanuts was 70 percent.

The study seems to support the claim that some of our allergies may be increasing in frequency because we avoid the triggers far too much. Furthermore, these results may lead physicians to consider new approaches to the way they deal with early childhood allergies.

In the case of peanut allergies, for example, the majority of children should be regularly exposed to peanuts in order to better develop a tolerance toward them. This is contrary to the general advice given in the recent past, which was to completely avoid peanut based products before the age of three years.

Whether these results can be generalized to other common environmental allergens has yet to be determined. In the meantime, don’t be afraid to lengthen your own personal “five-second rule” when you drop a piece of candy—it might actually be good for your immune system.